From ee28648cb2b4d4ab5c2eb8199ea86675fe19016b Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime.ripard@free-electrons.com>
Date: Thu, 29 Sep 2016 22:53:12 +0200
Subject: clk: sunxi-ng: Remove the use of rational computations

While the rational library works great, it doesn't really allow us to add
more constraints, like the minimum.

Remove that in order to be able to deal with the constraints we'll need.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/clk/sunxi-ng/Kconfig    |  3 ---
 drivers/clk/sunxi-ng/ccu_nkm.c  | 31 ++++++++++++-----------
 drivers/clk/sunxi-ng/ccu_nkmp.c | 37 ++++++++++++++--------------
 drivers/clk/sunxi-ng/ccu_nm.c   | 54 +++++++++++++++++++++++++++++++----------
 4 files changed, 74 insertions(+), 51 deletions(-)

--- a/drivers/clk/sunxi-ng/Kconfig
+++ b/drivers/clk/sunxi-ng/Kconfig
@@ -36,17 +36,14 @@ config SUNXI_CCU_NK
 
 config SUNXI_CCU_NKM
 	bool
-	select RATIONAL
 	select SUNXI_CCU_GATE
 
 config SUNXI_CCU_NKMP
 	bool
-	select RATIONAL
 	select SUNXI_CCU_GATE
 
 config SUNXI_CCU_NM
 	bool
-	select RATIONAL
 	select SUNXI_CCU_FRAC
 	select SUNXI_CCU_GATE
 
--- a/drivers/clk/sunxi-ng/ccu_nkm.c
+++ b/drivers/clk/sunxi-ng/ccu_nkm.c
@@ -9,7 +9,6 @@
  */
 
 #include <linux/clk-provider.h>
-#include <linux/rational.h>
 
 #include "ccu_gate.h"
 #include "ccu_nkm.h"
@@ -28,21 +27,21 @@ static void ccu_nkm_find_best(unsigned l
 	unsigned long _n, _k, _m;
 
 	for (_k = 1; _k <= nkm->max_k; _k++) {
-		unsigned long tmp_rate;
-
-		rational_best_approximation(rate / _k, parent,
-					    nkm->max_n, nkm->max_m, &_n, &_m);
-
-		tmp_rate = parent * _n * _k / _m;
-
-		if (tmp_rate > rate)
-			continue;
-
-		if ((rate - tmp_rate) < (rate - best_rate)) {
-			best_rate = tmp_rate;
-			best_n = _n;
-			best_k = _k;
-			best_m = _m;
+		for (_n = 1; _n <= nkm->max_n; _n++) {
+			for (_m = 1; _n <= nkm->max_m; _m++) {
+				unsigned long tmp_rate;
+
+				tmp_rate = parent * _n * _k / _m;
+
+				if (tmp_rate > rate)
+					continue;
+				if ((rate - tmp_rate) < (rate - best_rate)) {
+					best_rate = tmp_rate;
+					best_n = _n;
+					best_k = _k;
+					best_m = _m;
+				}
+			}
 		}
 	}
 
--- a/drivers/clk/sunxi-ng/ccu_nkmp.c
+++ b/drivers/clk/sunxi-ng/ccu_nkmp.c
@@ -9,7 +9,6 @@
  */
 
 #include <linux/clk-provider.h>
-#include <linux/rational.h>
 
 #include "ccu_gate.h"
 #include "ccu_nkmp.h"
@@ -29,24 +28,24 @@ static void ccu_nkmp_find_best(unsigned
 	unsigned long _n, _k, _m, _p;
 
 	for (_k = 1; _k <= nkmp->max_k; _k++) {
-		for (_p = 1; _p <= nkmp->max_p; _p <<= 1) {
-			unsigned long tmp_rate;
-
-			rational_best_approximation(rate / _k, parent / _p,
-						    nkmp->max_n, nkmp->max_m,
-						    &_n, &_m);
-
-			tmp_rate = parent * _n * _k / (_m * _p);
-
-			if (tmp_rate > rate)
-				continue;
-
-			if ((rate - tmp_rate) < (rate - best_rate)) {
-				best_rate = tmp_rate;
-				best_n = _n;
-				best_k = _k;
-				best_m = _m;
-				best_p = _p;
+		for (_n = 1; _n <= nkmp->max_n; _n++) {
+			for (_m = 1; _n <= nkmp->max_m; _m++) {
+				for (_p = 1; _p <= nkmp->max_p; _p <<= 1) {
+					unsigned long tmp_rate;
+
+					tmp_rate = parent * _n * _k / (_m * _p);
+
+					if (tmp_rate > rate)
+						continue;
+
+					if ((rate - tmp_rate) < (rate - best_rate)) {
+						best_rate = tmp_rate;
+						best_n = _n;
+						best_k = _k;
+						best_m = _m;
+						best_p = _p;
+					}
+				}
 			}
 		}
 	}
--- a/drivers/clk/sunxi-ng/ccu_nm.c
+++ b/drivers/clk/sunxi-ng/ccu_nm.c
@@ -9,12 +9,42 @@
  */
 
 #include <linux/clk-provider.h>
-#include <linux/rational.h>
 
 #include "ccu_frac.h"
 #include "ccu_gate.h"
 #include "ccu_nm.h"
 
+struct _ccu_nm {
+	unsigned long	n, max_n;
+	unsigned long	m, max_m;
+};
+
+static void ccu_nm_find_best(unsigned long parent, unsigned long rate,
+			     struct _ccu_nm *nm)
+{
+	unsigned long best_rate = 0;
+	unsigned long best_n = 0, best_m = 0;
+	unsigned long _n, _m;
+
+	for (_n = 1; _n <= nm->max_n; _n++) {
+		for (_m = 1; _n <= nm->max_m; _m++) {
+			unsigned long tmp_rate = parent * _n  / _m;
+
+			if (tmp_rate > rate)
+				continue;
+
+			if ((rate - tmp_rate) < (rate - best_rate)) {
+				best_rate = tmp_rate;
+				best_n = _n;
+				best_m = _m;
+			}
+		}
+	}
+
+	nm->n = best_n;
+	nm->m = best_m;
+}
+
 static void ccu_nm_disable(struct clk_hw *hw)
 {
 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
@@ -61,24 +91,22 @@ static long ccu_nm_round_rate(struct clk
 			      unsigned long *parent_rate)
 {
 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
-	unsigned long max_n, max_m;
-	unsigned long n, m;
+	struct _ccu_nm _nm;
 
-	max_n = 1 << nm->n.width;
-	max_m = nm->m.max ?: 1 << nm->m.width;
+	_nm.max_n = 1 << nm->n.width;
+	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
 
-	rational_best_approximation(rate, *parent_rate, max_n, max_m, &n, &m);
+	ccu_nm_find_best(*parent_rate, rate, &_nm);
 
-	return *parent_rate * n / m;
+	return *parent_rate * _nm.n / _nm.m;
 }
 
 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
 			   unsigned long parent_rate)
 {
 	struct ccu_nm *nm = hw_to_ccu_nm(hw);
+	struct _ccu_nm _nm;
 	unsigned long flags;
-	unsigned long max_n, max_m;
-	unsigned long n, m;
 	u32 reg;
 
 	if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate))
@@ -86,10 +114,10 @@ static int ccu_nm_set_rate(struct clk_hw
 	else
 		ccu_frac_helper_disable(&nm->common, &nm->frac);
 
-	max_n = 1 << nm->n.width;
-	max_m = nm->m.max ?: 1 << nm->m.width;
+	_nm.max_n = 1 << nm->n.width;
+	_nm.max_m = nm->m.max ?: 1 << nm->m.width;
 
-	rational_best_approximation(rate, parent_rate, max_n, max_m, &n, &m);
+	ccu_nm_find_best(parent_rate, rate, &_nm);
 
 	spin_lock_irqsave(nm->common.lock, flags);
 
@@ -97,7 +125,7 @@ static int ccu_nm_set_rate(struct clk_hw
 	reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
 	reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 
-	writel(reg | ((m - 1) << nm->m.shift) | ((n - 1) << nm->n.shift),
+	writel(reg | ((_nm.m - 1) << nm->m.shift) | ((_nm.n - 1) << nm->n.shift),
 	       nm->common.base + nm->common.reg);
 
 	spin_unlock_irqrestore(nm->common.lock, flags);
